The present disclosure relates to a controller and a control method for an internal combustion engine that perform combustion starting, through which engine is started without using the starter motor.
Japanese Laid-Open Patent Publication No. 2005-155362 discloses a controller that performs combustion starting in response to a restarting request generated in a stopping period when the crankshaft is rotating inertially after fuel injection is stopped. The combustion starting is restarting of the internal combustion engine by resuming fuel injection and performing ignition without using the starter motor.
When the engine is in the stopping period and rotating at a low engine speed, specifically, when the inertial rotation force of the crankshaft is smaller than the compression reaction force acting on a cylinder in a compression stroke and thus the piston cannot pass the top dead center, the controller injects fuel into another cylinder that is in an expansion stroke.
The controller then performs ignition in that cylinder to apply torque to the crankshaft in the forward rotational direction such that the torque in the forward rotational direction exceeds the compression reaction force. In this manner, the engine is restarted without using the starter motor.